Linux - "cannot execute: required file not found" error

In Bash, if you are running a script, for example installation, and it throws error

$./my_installer

-bash: ./my_installer: cannot execute: required file not found

and you are certain that all files requires exist. You may want to check what SHELL was used to write the install script.

If you are using BASH but the script is written by KSH and KSH is not installed, this error will happen.